Investigations of Systemic Lupus Erythematosus will be undertaken utilizing pedigree Shetland Sheepdogs as an animal model. Preliminary studies indicate that Shelty dogs in the U.S.A. are a breed at risk for systemic lupus erythematosus. We will purchase and maintain a small but representative sampling of these animals for additional studies which will include: (1) further development of the animal model utilizing immunologic and pathologic criteria, (2) genetic tests to evaluate the mode (s) of inheritance, and (3) virologic tests to determine the role of a horizontally transmitted virus in canine SLE.